| ((imm >> (31 - 7)) & 0x80); /* b[31] -> b[7] */
}
-/* Return TRUE if IMM is a valid floating-point immediate; return FALSE
- otherwise. */
+/* Return TRUE if the single-precision floating-point value encoded in IMM
+ can be expressed in the AArch64 8-bit signed floating-point format with
+ 3-bit exponent and normalized 4 bits of precision; in other words, the
+ floating-point value must be expressable as
+ (+/-) n / 16 * power (2, r)
+ where n and r are integers such that 16 <= n <=31 and -3 <= r <= 4. */
+
static bfd_boolean
aarch64_imm_float_p (uint32_t imm)
{
- /* 3 32222222 2221111111111
+ /* If a single-precision floating-point value has the following bit
+ pattern, it can be expressed in the AArch64 8-bit floating-point
+ format:
+
+ 3 32222222 2221111111111
1 09876543 21098765432109876543210
- n Eeeeeexx xxxx0000000000000000000 */
- uint32_t e;
+ n Eeeeeexx xxxx0000000000000000000
+
+ where n, e and each x are either 0 or 1 independently, with
+ E == ~ e. */
- e = (imm >> 30) & 0x1;
- if (e == 0)
- e = 0x3e000000;
+ uint32_t pattern;
+
+ /* Prepare the pattern for 'Eeeeee'. */
+ if (((imm >> 30) & 0x1) == 0)
+ pattern = 0x3e000000;
else
- e = 0x40000000;
- return (imm & 0x7ffff) == 0 /* lower 19 bits are 0 */
- && ((imm & 0x7e000000) == e); /* bits 25-29 = ~ bit 30 */
+ pattern = 0x40000000;
+
+ return (imm & 0x7ffff) == 0 /* lower 19 bits are 0. */
+ && ((imm & 0x7e000000) == pattern); /* bits 25 - 29 == ~ bit 30. */
}
-/* Note: this accepts the floating-point 0 constant. */
+/* Like aarch64_imm_float_p but for a double-precision floating-point value.
+
+ Return TRUE if the value encoded in IMM can be expressed in the AArch64
+ 8-bit signed floating-point format with 3-bit exponent and normalized 4
+ bits of precision (i.e. can be used in an FMOV instruction); return the
+ equivalent single-precision encoding in *FPWORD.
+
+ Otherwise return FALSE. */
+
static bfd_boolean
-parse_aarch64_imm_float (char **ccp, int *immed)
+aarch64_double_precision_fmovable (uint64_t imm, uint32_t *fpword)
+{
+ /* If a double-precision floating-point value has the following bit
+ pattern, it can be expressed in the AArch64 8-bit floating-point
+ format:
+
+ 6 66655555555 554444444...21111111111
+ 3 21098765432 109876543...098765432109876543210
+ n Eeeeeeeeexx xxxx00000...000000000000000000000
+
+ where n, e and each x are either 0 or 1 independently, with
+ E == ~ e. */
+
+ uint32_t pattern;
+ uint32_t high32 = imm >> 32;
+
+ /* Lower 32 bits need to be 0s. */
+ if ((imm & 0xffffffff) != 0)
+ return FALSE;
+
+ /* Prepare the pattern for 'Eeeeeeeee'. */
+ if (((high32 >> 30) & 0x1) == 0)
+ pattern = 0x3fc00000;
+ else
+ pattern = 0x40000000;
+
+ if ((high32 & 0xffff) == 0 /* bits 32 - 47 are 0. */
+ && (high32 & 0x7fc00000) == pattern) /* bits 54 - 61 == ~ bit 62. */
+ {
+ /* Convert to the single-precision encoding.
+ i.e. convert
+ n Eeeeeeeeexx xxxx00000...000000000000000000000
+ to
+ n Eeeeeexx xxxx0000000000000000000. */
+ *fpword = ((high32 & 0xfe000000) /* nEeeeee. */
+ | (((high32 >> 16) & 0x3f) << 19)); /* xxxxxx. */
+ return TRUE;
+ }
+ else
+ return FALSE;
+}
+
+/* Parse a floating-point immediate. Return TRUE on success and return the
+ value in *IMMED in the format of IEEE754 single-precision encoding.
+ *CCP points to the start of the string; DP_P is TRUE when the immediate
+ is expected to be in double-precision (N.B. this only matters when
+ hexadecimal representation is involved).
+
+ N.B. 0.0 is accepted by this function. */
+
+static bfd_boolean
+parse_aarch64_imm_float (char **ccp, int *immed, bfd_boolean dp_p)
{
char *str = *ccp;
char *fpnum;
LITTLENUM_TYPE words[MAX_LITTLENUMS];
int found_fpchar = 0;
+ int64_t val = 0;
+ unsigned fpword = 0;
+ bfd_boolean hex_p = FALSE;
skip_past_char (&str, '#');
- /* We must not accidentally parse an integer as a floating-point number. Make
- sure that the value we parse is not an integer by checking for special
- characters '.' or 'e'.
- FIXME: This is a hack that is not very efficient, but doing better is
- tricky because type information isn't in a very usable state at parse
- time. */
fpnum = str;
skip_whitespace (fpnum);
if (strncmp (fpnum, "0x", 2) == 0)
- return FALSE;
+ {
+ /* Support the hexadecimal representation of the IEEE754 encoding.
+ Double-precision is expected when DP_P is TRUE, otherwise the
+ representation should be in single-precision. */
+ if (! parse_constant_immediate (&str, &val))
+ goto invalid_fp;
+
+ if (dp_p)
+ {
+ if (! aarch64_double_precision_fmovable (val, &fpword))
+ goto invalid_fp;
+ }
+ else if ((uint64_t) val > 0xffffffff)
+ goto invalid_fp;
+ else
+ fpword = val;
+
+ hex_p = TRUE;
+ }
else
{
+ /* We must not accidentally parse an integer as a floating-point number.
+ Make sure that the value we parse is not an integer by checking for
+ special characters '.' or 'e'. */
for (; *fpnum != '\0' && *fpnum != ' ' && *fpnum != '\n'; fpnum++)
if (*fpnum == '.' || *fpnum == 'e' || *fpnum == 'E')
{
return FALSE;
}
- if ((str = atof_ieee (str, 's', words)) != NULL)
+ if (! hex_p)
{
- unsigned fpword = 0;
int i;
+ if ((str = atof_ieee (str, 's', words)) == NULL)
+ goto invalid_fp;
+
/* Our FP word must be 32 bits (single-precision FP). */
for (i = 0; i < 32 / LITTLENUM_NUMBER_OF_BITS; i++)
{
fpword <<= LITTLENUM_NUMBER_OF_BITS;
fpword |= words[i];
}
+ }
- if (aarch64_imm_float_p (fpword) || (fpword & 0x7fffffff) == 0)
- *immed = fpword;
- else
- goto invalid_fp;
-
+ if (aarch64_imm_float_p (fpword) || (fpword & 0x7fffffff) == 0)
+ {
+ *immed = fpword;
*ccp = str;
-
return TRUE;
}
bfd_boolean res1 = FALSE, res2 = FALSE;
/* N.B. -0.0 will be rejected; although -0.0 shouldn't be rejected,
it is probably not worth the effort to support it. */
- if (!(res1 = parse_aarch64_imm_float (&str, &qfloat))
+ if (!(res1 = parse_aarch64_imm_float (&str, &qfloat, FALSE))
&& !(res2 = parse_constant_immediate (&str, &val)))
goto failure;
if ((res1 && qfloat == 0) || (res2 && val == 0))
case AARCH64_OPND_SIMD_FPIMM:
{
int qfloat;
- if (! parse_aarch64_imm_float (&str, &qfloat))
+ bfd_boolean dp_p
+ = (aarch64_get_qualifier_esize (inst.base.operands[0].qualifier)
+ == 8);
+ if (! parse_aarch64_imm_float (&str, &qfloat, dp_p))
goto failure;
if (qfloat == 0)
{
projects / fpga / lx-cpu1 / binutils-tumbl.git / blobdiff